By: Gary Bates, Director of the University of Tennessee Beef and Forage Center
Before you can accurately apply the right amount of herbicide to a field, you have to know how much volume the sprayer is applying to each acre. Sprayer calibration is not difficult, but it can be challenging if you have never seen it done before. Here are two simple methods of spraying calibration:
Spray and acre method: In this method, you fill the tank with water, spray an acre, then see how much water it takes to refill the tank. Pretty simple, but takes a little time. You also have to be exact on the land area measurement.
1/128th method: this is a relatively fast and accurate method.
1. Select a course length based on nozzle spacing (from chart below)
2. Measure out course in field to be sprayed.
3. Measure time to drive course. Use a comfortable gear and speed. Take the
average of three trips.
4. Park tractor and catch the ouput from one nozzle for the time found in step 3.
5. Measure in ounces. This will equal the gallons per acre output.